Quick freezing system



1933. R. v. GR AYSON ET AL 1,924,988

QUICK FREEZING SYSTEM Filed Dec. 16, 1931' 7 Sheets-Sheet 1 IHHHI ngwuentom R firaysan and E G-fiafie n ez" w 0 Hi Aug. 29, 1933. R. v.GRAYSON ET AL QUICK FREEZING SYSTEM Filed Dec. 16, 1951 7 Sheets-Sheet 2"6 w n e D n 3 K Grays'onahd Efiflalle 6Z1 5 M E by ornes Aug. 29, 1933.R. v. GRAYSON ET AL 1,924,938

I QUICK FREEZING SYSTEM Filed D60. 16, 1931 7 Sheets-Sheet 3 Summer;

I @mm gmmws 2 1933- R. v. GRAYSON ET AL 1,924,988

QUICK FREEZING SYSTEM 7 Filed Dec. 16, 1931 '7 Sheets-Sheet 4 Aug. 29,1933. R. v. GRAYSON ET AL QUICK FREEZING SYSTEM Filed Dec. 16, 1931 7Sheets-Sheet 5 ISnventor R Grayson 4E Z78 flier w m R. V. GRAYSON El ALQUICK FREEZING SYSTEM Aug. 29, 1933.

'7 Sheets-Sheet 6 Filed Dec. 16, 1931 3nventor (Ittorneg qson E 2:. v.Gra and .Ba Zen l l l l 1 l 1 I I I H HHMwHH MI V A IHNV FHH H Hm wH. H1

Aug. 29, 1933. R. v. GRAYSON ET AL QUICK FREEZ ING SYSTEM Filed Dec. 16,1931 7 Sheets-Sheet '7 Zhwentor; 12.1 aragson. M4

G. Ballenger I @Q'. (IttornegS Patented Aug. 29, 1933 QUICK FREEZINGSYSTEM Ralph V. Grayson and Edgar G. Ballenger,

Atlanta, Ga.; said Grayson asslgnor to Patent and Security HoldingCorporation, Tampa, Fla., a corporation of Florida Application December16, 1931 Serial No. 581,451

17 Claims.

This invention relates to the quick freezing of perishable products,especially foodstuffs and has for its general objects the provision ofmethods and apparatus for the continuous quick freezing of packagedperishables, or the continuous freezing of unpackaged small units of theproduct which are then packed into a large bulk package, the intersticesfilled with liquid and the whole frozen into an integral block throughthe reflex chilling of the matrix liquid by the frozen units themselves.

Another object of the invention is the provision of a continuousfreezing system in which the product in thin walled receptacles whichmay be paper, is subject to heat exchange with the liquid freezingmedium directly through the walls of the receptacles. 1

A further object of the invention is to provide a method and apparatusfor continuous refrigeration, by causing the objects to be frozen totravel through circulating brine or air, the freezing medium beingchilled by passing in heat exchanging relation with respect to carbondioxide ice or snow. When snow'is employed, it may be formed in situ inthe region of heat exchange.

Still another object of the invention is the provision of a flexiblebelt with molded cups for receiving the product to be frozen, andpassing in refrigerating relation to the brine or air, and beingdeformed at the end of the freezing phase of its cycle so asautomatically to eject the frozen units.

Another object of the invention is the provision of brine or air tunnelsof such shape as to form between them valleys of downwardly convergentcross section adapted to be charged with carbon dioxide ice, which ingrowing smaller as it evaporates, maintains contact with said walls asit settles in said valleys by virtue of their shape.

A further object of the invention is the construction of apparatus foreffecting eflicient heat exchange between the brine or air and thecarbon dioxide, comprising tunnels of preferably triangular crosssection and undulating laterally whereby not only to present maximumsurface to the refrigerating medium but having the undulatingwalls'thereof assume the role of baflles for bringing the medium to berefrigerated into more intimate contact with the surface of said walls.

Other objects of the invention will appear as the following descriptionof preferred and practical embodiments thereof proceeds.

In the drawings which accompany and form a part of the followingspecification and in which the same characters of reference have beenused.

throughout the several figures to designate identical parts:

Figure 1 is a longitudinal vertical section, somewhat diagrammatic of acontinuous quick freezing system embodying the principles of the presentinvention;

Figure 2 is across section taken along the line 2-2 of Figure 1;

Figure 3 is a perspective view showing a detail of construction;

Figure 4 is a plan view partly in section indiv cating the means forregenerating the carbon dioxide;

Figure 5 is a vertical section taken on the line 5-5 of Figure 4;

Figure 6 is a side elevation partly in section of one of the conveyorracks;

Figure '7 is a front elevation of one of said racks, part being brokenaway;

Figure 8 is an end view of the door of one of 75 the carbon dioxidetunnels;

Figure 9 is a longitudinal section taken along the line 99 of Figure 8;

Figure 10 is a plan view of a modified form of the invention showing theendless belts with 80 molded cups;

Figure 11 is a longitudinal view partly in section and partlydiagrammatic, taken along the line 11-11 of Figure 10;

Figure 12 is a cross section taken along the line 1212 of Figure 11;

Figure 1 3 is a vertical section through one end of the molded beltshowing the deforming roller;

Figure 14 is a section taken along the line 1414 of Figure 13;

Figure 15 is a vertical section through a bulk container loaded withsmall frozen units;

Figure 16 is a plan view through a section of modified form of beltingfor forming frozen triangular bars; 95

Figure 1'7 is a vertical section taken along the line 17-17 of Figure16;

Figure 18 is a section through an end of the belt shown in Figure 17passing over a deforming roller;

Figure 19 is a front elevation of the defaming roller;

Figure 20 is a plan view of the ripple coil;

Figure 21 is a vertical section taken along the line 2121 of Figure 20;

Figure 22 is a section taken along the line 22-22 of Figure 21; and

Figure 23 is a vertical section through the system which employs theripple coil, showing the circulation of brine.

til:

Referring now in detail to the several figures and first adverting tothat form of the invention shown in Figures 1 to 9, inclusive, thenumeral 1 represents a brine tank through which packaged products 2 tobe frozen are made to travel by means of a conveyor 3, the speed of theconveyor being regulated so that by the time the packages have traversedthe brine bath the products are in frozen state.

The packages may be of any suitable size or shape and the receptaclesmay be of any suitable material. Beneath the brine tank 1 is a series oftunnels 4 through which the brine circulates and is refrigerated. Inorder to present the brine to the action of the refrigerant in the formof a relatively thin layer or film, the tunnels are provided withinterior cores 5 conforming in cross-sectional shape to that of thetunnels. The brine flows through the space between the walls 6 of thecores and the outer walls 7 of the tunnels. In the present instance thetunnels are of triangular cross section and they are arranged side byside so as to provide valleys in between, whose sides converge towardthe bottoms of said valleys. The valleys are designed to be charged witha suitable refrigerant. In the present instance carbon dioxide ice isselected and blocks of the carbon dioxide ice are sawed in two,diagonally forming wedge-shaped blocks which fit the shape of thevalleys. As the blocks grow smaller through evaporation they settlelower in the valleys, the surfaces of said blocks maintaining intimatecontact with the sides of said valleys. It is apparent that thetriangular shape of the tunnels produces the most efficientheat-interchanging conditions with respect to the refrigerant.

Figures 8 and 9 show details of construction, the former figures showinga door 9 adapted to close the ends of the valleys. This door is held inplace by suitable closure fasteners such as the cleats 10. By removingthe doors the blocks of carbon dioxide may be pushed end-wise into thevalleys. It is of course understood that while blocks of carbon dioxideice of triangular cross section are preferred, the ice may be of anyirregular shaped or sized pieces.

Figure 1 shows that the brine circulates through the tunnels 4,discharging into a header 11 at one end. A pump 12 in said header picksup the refrigerated brine and discharges it into the brinetank 1. Theopposite: end of said brine tank is provided with a baffle 13terminating at a suitable distance below the top of said brine tank bymeans of which a constant level of brine is maintained in said tank. Thespent brine overflows said baflle into a header 14 with which theopposite ends of the tunnels 4 communicate. Figures 1 and 2 illustratean embodiment of the invention in which the floor of the brine tank 1rests upon the apices of the tunnels 4. This is only an exemplaryconstruction and it is to be understood that the brine tank may besupported in any suitable manner and may have any other positionalrelation to the tunnels, as may be desired. The entire unit comprisingthe brine tank refrigerating tunnels and appurtenant mechanism ispreferably lagged by a heavy layer of insulation indicated at 15 inFigure 1.

Means may be provided for regenerating the carbon dioxide. Such meansare shown in Fig ures 2, 4 and 5, comprising pipes 16 opening into thecarbon dioxide valleys or troughs at one end,

as shown in Figure 4 and, for convenience extending through the cores 5of the tunnels as shown in Figures 2 and 5. Said pipes communicate witha manifold 17 which leads to a compressor 18 in which the gaseous carbondioxide eventuating from the evaporation of the ice is compressed andfrom it is discharged into a condensor 19 where it is liquefied andstored as a liquid in the tank 20.

The carbon dioxide troughs or valleys are preferably so sealed againstatmospheric leakage that there is but little dilution of the carbondioxide gas.

In Figure 1, which shows diametrically an entire quick freezing system,the packages 2 of the product to be frozen are drawn by the conveyor 3first through the brine and then elevated so as to clear the brine tankand then depressed so that the package is dipped into a bath of water 21in a tank 22, which may be suitably heated if found necessary from anysource such as the burner 23.

The conveyor preferably comprises spaced chains 24 and 25, to which nonovelty is ascribed, passing over suitable sprockets. The chains supportat intervals, transverse bars 26 from which are suspended the racks 27,best shown in Figures 6 and '7. Said racks are preferably in the form ofenclosures extending substantially the width of the brine tank andhaving links 28 at their outer sides pivotally connected to thetransverse bars 26. Said racks are provided with a series of apertures29 in the bottom walls thereof through which project the major portionsof the packages 2. The packages are preferably tapered more or less andthe racks 2'7 have the side walls thereof correspondingly tapered sothat when the packages are inserted through the apertures 29 they jamagainst the side walls of the rack so that they will not fall entirelythrough. The size of the holes is so apportioned relative to thepackages as to cause the latter to form a substantial seal againstleakage of the brine into the interior of the enclosures forming theracks. The forward wall 30 of the rack is preferably made somewhathigher than the rearward wall 31, so that the wave of liquid in advanceof the rack, caused by the travel of the same through the brine, willnot overflow the top of the rack. The hinged lid 32 preferably closesthe top of the rack and swings freely to an open position when the rack,together with the package of frozen product is upset.

The object of the Water bath 21 is to defrost the contacting surfaces ofthe package and rack, and it will be observed that the rack dipssufficiently into the water bath to immerse the lower part of said rack,but not sufliciently to create a risk of the water entering the top ofthe rack. If desired, a spray of pure water may be directed upon theracks and packages for removing any vestige of brine. Figure 1 shows arose 23 for providing such a spray.

After the racks have emerged from the water bath they are elevated insuch a way as to come in contact with the inverter 34. This may be ofany suitable shape or construction, its sole object being to upset theracks so as to permit the gravital discharge of the packages of frozenproduct whose adherence to the racks has been loosened by the meltingaction of the water bath. The inverter is in advance of a chute 35 downwhich the frozen packages slide when discharged from the inverted racks.The racks then proceed upwardly on the conveyor back to the point ofbeginning, fresh packages of the product to be frozen being supplied tothem at some point in their return course. Figure 1 shows that a dry-airblast from a suitable conduit 36 may be blown upon the packages adjacentthe point of discharge from the racks, for drying them so that they willnot freeze together later, in cold storage.

The freezing of foodstufis and other products in large bulk packages isordinarily difficult to accomplish owing to the thickness of the mass ofthe product, and the fact that the freezing begins with the outside andthat as soon as a thin film of the product has been frozen it acts as aninsulator, retarding the transmission of heat from the irmermost partsof the mass. Under ordinary methods of freezing, therefore, it isimpracticable to freeze large masses in bulk on account of theinordinate amount of time required for the freezing operation, and thenwith the risk that the core portion of the mass will be imperfectlyfrozen.

The present invention proposes the freezing of small, unpackaged unitsof the product and the aggregating of these in a large bulk package.Figure 15 illustrates this concept, the numeral 3'7 designating a largecontainer, the same being packed with the small frozen units 38. Theintersticial spaces between the units are filled with a liquid, whichmay be a syrup of the frozen product, and the temperature of the smallunits is relied upon to freeze the liquid or syrup, binding the smallunits together into an integral frozen mass.

V Apparatus for carrying out the freezing of the small units isillustrated in Figures 10 to 19. In.

Figures 10 and 11, an endless belt conveyor 39 is shown, the same beingmolded with wells or depressions 40 forming receptacles, receiving theunpackaged product to be frozen which may be charged into them in anysuitable manner, as for instance, by means of the conduit 41. The beltconveyor passes through a freezing chamber. 42 in which air ispreferably substituted for liquefied carbon dioxide in the valleysbetween the tunnels.

The endless belt beyond the point of its emergence from the freezingchamber passes over a barrel-shaped roller 45, by means of which thebelt is distorted transversely, as well as longitudinally, deforming thewells or depressions, ejecting the frozen masses, as is clearlyillustrated at 46 in Figure 11. These masses are suitably collected andpacked into the bulk container and frozen into an integral whole in themanner already described.

In a modified form of the invention the endless belt is molded withstraight sides 47 and 48 (see Fig. 16) and between them, with transversetroughs 49. These troughs may be charged with the product to be frozenand the belt passed through the refrigerating chamber in the same manneras has been described in connection with that form of the inventionshown in Figures 10 and 11. The frozen bars of triangular cross sectionare ejected, as illustrated in Fig. 18 through the action of a deformingroller 50.

If preferred, the troughs 49 may receive metallic pans 49 formed withtroughs which conform to the troughs molded in the belt. These metallicpans, or sections, may be of any desired length and serve not only tokeep the product Figures 20 and 21 illustrate a freezing which thetunnels do not extend rectilinearly in a longitudinal direction, butundulate laterally.'

Figure 20 shows a series of such tunnels, the

undulating lines 52 representing the bottomsbf the valleys between saidtunnels. A freezingunit of this type has the advantage of not only 'ex-.tending the surface of the tunnel within'a given length of unit, but bycontinually changing the direction of the brine or air circulatingthrough said tunnel, it causes said brine or air to im-' pingeintimately against the walls of said tunnel at the bends, reducingsluggishness of circulation due to skin friction and thus greatlyenhancing the heat-exchanging activity of the unit, and this same effectis also produced in the freezing medium, carbon dioxide gas, which maycirculate through the valleys on the outside of said tunnels.

Figures 21 -and 22 also illustrate the principles of a system in whichthe carbon dioxide snow is produced in situ, in the valleys, and thecarbon dioxide gas eventuating from the evaporation of said snowcollected for the purpose of regeneration. In this phase of theinvention" the bottom 53 of the brine tank is arranged, at a convenientdistance above the spices 54 of, the triangular tunnels. A system ofpiping 55 occupies the intervening space, said piping being connected toa source of carbon dioxide gas under pressure, or liquefied carbondioxide. A plurality of expansion valves 56 are intercalated in the pipehaving orifices opening through the top walls 57 of the valleys betweenthe tunnels. ,Carbon dioxide in liquid or gaseous form is dischargedfrom said orifices into said valleys and immediately changes its stateinto snow, which evaporating, produces the desired refrigerative effect.The gas resulting from the expansion of the snow traverses the valleys,being pumped therefrom through conduits 57, said conduits returningthrough the cores of the tunnels and entering'a manifold 58 which leadsto compressingand condensing apparatus not shown in these figures butwhich is diagrammatically shown in connectionwith that form of theinvention illustrated in Figure 4.

In all forms of the invention the tunnels may be provided with fins orribs 58 on the interior of the tunnel walls for further increasing theheat-exchanging eiflciency'of said tunnels. In the event that freezing:of the walls may occur, a

system of defrosting pipes 59 'may be provided off from the tunnels andthe calcium chloride sprayed upon interiorsurfaces thereof and fromwhich it may be drained, together with the thawed condensate by suitablemeans, not shown.

While we have in the above specification de- J-flr scribed severalpractical embodiments for carrying out our invention, it is to beunderstood that the invention concerns itself primarily with a broadconcept of quick freezing involving the heat-interchange between carbondioxide and a lu l circulating medium executing part of its circulatorypath through triangular tunnels, and that the details of constructionand arrangement of the several units and parts may be varied within widelimits and still be within the scope of the invention as claimed.

What we claim is:

1. Quick freezing system comprising means providing a refrigeratingbath, means providing a thawing bath, drying means, and means fortransporting packages of the product to be frozen successively throughsaid refrigerating bath and thawing bath and in operative relation tosaid drying means, at a rate of speed to accomplish freezing of theproduct in its transit through the refrigerating bath, the transportingmeans in-' cluding conveyor racks, each comprising a shield portionintersecting the plane of the level of the brine when in transittherethrough, and fitting in fluid-tight manner about the mouths of saidpackages, leaving the lower portions of said pack ages directly exposedto the brine, and upsetting means beyond said drying means engageable bythe unit constituted by said rack and packages for effecting thegravital discharge of said packages.

2. Quick freezing system comprising a conduit for a circulating freezingmedium, a part of said conduit including tunnels, the adjacent outerwalls of which converge downwardly forming a chamber for solidrefrigerant.

3. Quick freezing system as claimed in claim 2, the tunnels having acore defining with the outer walls of said tunnels narrow spaces for thepassage of the freezing medium.

4. Quick freezing system comprising a conduit for a circulating freezingmedium, a part of said conduit including a plurality of tunnels arrangedside by side and connected in parallel, said tunnels being of triangularcross section and having their adjacent outer walls convergingdownwardly forming a chamber for'solid refrigerant narrowing toward thebottom whereby the refrigerant maintains engagement with the walls ofsaid chambers notwithstanding its diminution in mass throughevaporation, and a conveyor for passing objects to be frozen throughanother part of said conduit.

5. Quick freezing system comprising a brine tank and a plurality oftunnels connected in parallel to said brine tank at opposite sides, apump for circulating brine through said tank and tunnels, the walls ofsaid tunnels defining chambers for maintaining solid refrigerant inheat-exchange relation to said brine through said walls.

6. Quick freezing system as claimed in claim 5 including a hollowinterior core for said tunnels, and means for conducting evaporatedrefrigerant from said chambers through said cores.

7. Quick freezing system comprising a conduit for a circulating freezingmedium, a part of said conduit including a plurality of tunnels arrangedside by side and connected in parallel, said tunnels being of triangularcross section and having their adjacent outer walls convergingdownwardly forming a chamber for solid refrigerant, said tunnels havinga laterally undulating contour.

8. In a freezing system, a refrigerating chamber and a conveyor passingtherethrough, said conveyor including racks swingably mounted andadapted to suspend packages of the product to be frozen in exposedstate.

9. In a freezing system as claimed in claim 8, the racks having the formof an enclosed chamber, having holes in the bottom through which themajor portions of the packages project.

10. Quick freezing system comprising means providing a refrigeratingbath, means comprising a thawing bath, and means for transportingpackages of the product to be frozen successively through saidrefrigerating bath and said thawing bath" at a rate of speed toaccomplish freezing of the product in its transit through therefrigerating bath, said transporting means including a conveyor andracks forming parts of said conveyor for suspending said packages insaid baths.

11. Quick freezing system comprising means providing a refrigeratingbath, means comprising a thawing bath, and means for transportingpackages of the product to be frozen successively through saidrefrigerating bath and said thawing bath at a rate of speed toaccomplish freezing of the product in its transit through therefrigerating bath, said transporting means including conveyor racks,each comprising a shield portion intersecting the plane of the level ofthe brine when in transit there-across, and fitting in fluid-tightmanner about the mouths of said packages, leaving the lower portions ofsaid packages directly exposed to the brine.

12. Quick freezing system comprising means providing a refrigeratingbath, means comprising a thawing bath, and means for transportingpackages of the product to be frozen successively through saidrefrigerating bath and said thawing bath at a rate of speed toaccomplish freezing of the product in its transit through therefrigerating bath, said transporting means including conveyor rackseach comprising a shield portion intersecting the plane of the level ofthe brine when in transit therethrough, and fitting in fluid-tightmanner about the mouths of said packages, leaving the lower portions ofsaid packages exposed to the brine, and hinged lid closing said shieldportions.

13. Quick freezing system comprising means providing a refrigeratingbath, means comprising a thawing bath, and means for transportingpackages of the product to be frozen successively through saidrefrigerating bath and said thawing bath at a rate of speed toaccomplish freezing of the product in its transit through therefrigerating bath, said transporting means including conveyor rackseach comprising a shield portion intersecting the plane 'of the level ofthe brine when in transit therethrough, and fitting in fluid-tightmanner about the mouths of said packages, leaving the lower portions ofsaid packages directly exposed to the brine, and upsetting means beyondsaid thawing means engageable by the unit constituted by said rack andpackages for effecting the gravital discharge of said packages from saidracks.

14. Quick freezing system comprising means providing a refrigeratingbath, means comprising a thawing bath, and means for transportingpackages of the product to be frozen successively M through saidrefrigerating bath and said thawing bath at a rate of speed toaccomplish freezing of the product in its transit through therefrigerating bath, said transporting means including conveyor racks,each comprising a shield portion, and fitting in fluid-tight mannerabout the mouths of said packages, leaving the lower portions of saidpackages directly exposed to the brine.

15. Quick freezing system comprising a con- 15G duit for a circulatingfreezing medium, a part parallel to said brine tank at opposite sides, apump for circulating brine through said tank and tunnels, the walls ofsaid tunnels defining chambers for maintaining solid refrigerant in heatexchanging relation to said brine through said walls, the latter havinga laterally undulating contour.

RALPH V. GRAYSON.

EDGAR G. BALLENGER.

